5th April 2013, 09:22 PM
6th April 2013, 12:23 AM
Re: HONDA CB750 SOHC
I continue from the previous post.
So this is the Cabton RTS 600 engine :
And a 250 version of the Cabton for which I could'nt find any info.Can it be single cylinder just like Indian had a single version of that engine in250cc called Arrow?I can't tell from this pic. but here it is:
And next the Indian engine.See how it has the timing side on the left of the engine while Cabton has it to the right.
The RTS had28hp/4000rpm the torque was5.0kg\3500rpm and a top speed of 130km/h.Why would they go to the trouble of copying as a mirror image is really a mystery to me,although we have to say that when
indian made that engine inspired by Triumph (TheWarrior is not a copy but is heavily influenced by the British school)
they made it also as a mirror image of the usual British practice of drive side on the left and timing side to the right.
So Cabton just went back to the British practice.(Why?).
It's also strange why did they pick this Indian to copy.The Warrior-Arrow-Super Scout was an effort of Indian to catch up
with the British who where doing great in the USA with the 500-650 twins.The engineer who designed these engines
was working for an outboard engine company(maybe Evinrude?) and wasn't aware of the different loads that a motorcycle
puts on the moving parts of the engine.So used to draw boat engines that more or less work in constant rpm he made a very weak engine which as soon as it came on the market it got a bad reliability name.So Indian beetwen paying the
repairs and trying to improve the engine for the next models went bankrupt and those where the last true made in USA
Indians.Not that they would'nt go out of bussines anyway but the warrior was the last nail in their coffin.
Mizuho Cabton didnt go very well either.To compete to the other brands in the market they followed a policy of low prices
mass production and deals with other manufacturers to develope together new engines.
In 1954 the year that the RTS 600 came out they had 800 workers but two years later the production stopped the factory
closed the doors and a few years later the founder,Shoichi Naito,suicided.
The policy of prices lower than the competition,mainly Honda and Meguro,meant less quality control,deteriorating quality of their products and loss of their good reputation.
Mizuho in Japan is considered to be a company that commited suicide.
Somehow the"technical lineage" was inherited by Kawasaki,I don't know how but propably by hiring the Cabton engineers.
Next pic the RTS 600.I could'nt find a better picture.This bike has a big story.Sunk in the sea after a huricane when almost new,saved,restored only to get burried in mud in some other natural disaster in the 80's
And this is the Indian Warrior TT version.A real beauty.
Here I have to say that all this story is very brief Cabton made about20 different models mostly postWW2 but the info is almost non excisting.As I read in a Japanese classic bike blog,even today there's a type of cylindrical exaust silencer
that is called"cabton muffler" (something like the "goldie"type silencer )but not many know what it is named from
and they think it is a brand.Which goes to show that not even there they know about Cabton.
Pictures that I see from Japanese classic bike meetings makes me believe that the twin is very rare While the single
appears more often but still not as often as Meguros Rikuos and the big four's old models.
They propably didn't sell to many in such a sort time they where in production although police forces did buy a few.
Didn't find any conection of Cabton with autorace or any other kind of racing and this is not surprising considering
the unreliability issues that I read about every time someone says something about the Cabton twins.
Next a 500 single with sidecar
And another single a 350 I think
Last edited by fkostas; 25th May 2013 at 11:14 PM.
7th April 2013, 08:59 PM
Re: HONDA CB750 SOHC
writing in the previous post about the Cabton choosing the wrong bike to copy reminded me of another
bike manufacturer that did the same wrong choice.
This manufacturer was Kitagawa motor works from Hamamatsu(where else?) and they existed from
There are written records of that co. importing 3 Sunbeams S8 and in 1954 they came out with a copy
of it which was actualy a scaled down copy because the Sumbeam was 500cc while the Liner as they
named it was 250cc.
next picture the Liner TW250.OHC twin,12,6hp/5500rpm,55mmX52mm.
And the Sumbeam S8 for comparison:
Very nice cast aluminum muffler by the way.
The Sunbeam was made by BSA, who owned the Sunbeam name,after they studied the blue prints of the BMW twin that they took home from Germany as war reparations.
BSA hired Erling Poppe who was involved in many projects pre and post war with Douglas bikes ,some
weird three wheeler and others.He even had his own motorcycle brand,Packman and Poppe(1922 1930),
but in all of these ventures he was using bought in engines.I didn't find any evidence that he ever
produce an engine designed by him.
Anyway BSA hired him and of course they didn't want to make a distinctively Germanic bike,there was strong antigerman feelings still in GB,so they chose to make an OHC parallel twin lengthwise on the frame so they use shaft final drive.
But the bike just wasn't good.It had a fragile shaft,head oiling issues and other handling problems.
Of course BSA improved it and had a new nodel before the year ended and they improved it more until
!956 when they stopped making it.
It never became popular,even though the later models are really sweet,and I wonder what drew
Kitagawa's attention on that specific model especialy in '54 when all the issues of the S8 where common knowledge(the S7 was introduced in 1946 and the S8 in '4 and the fact that they were not good sellers has been proved already.
So back at Hamamatsu thinks didn't look vey good either and in 1959 Yamaha bought the company or
bought part of it and eventually absorbed it.
Somehow it still exist inside Yamaha as Body Industries Yamaha(???).
Of course they had other models too like the Portly Robin.A side valve 150cc
Later a side valve with a 125 cc unit engine that imitates Showa's SH engine and it's called Liner Portly 125.
It shares this brochure with the TW:
In 1953 they make an OHC 150 cc version of this engine, 55 mmX63 mm,compresion 6.5:1,7hp at 5000rpm.
They raced it in the first Nagoya TT.
Sometime they also made a scooter the Crown KC:
I also found this brochure with a TW 250 with earles fork and deep valanced mudguards.I think it is the second version of the TW.The bike behind it is a 125 side valve Portly Robin.
Last edited by fkostas; 8th June 2013 at 02:17 PM.
13th April 2013, 01:58 PM
18th April 2013, 11:43 PM
19th April 2013, 01:28 AM
19th April 2013, 02:26 PM
20th April 2013, 01:33 PM
20th April 2013, 02:02 PM
22nd April 2013, 01:07 PM
22nd April 2013, 02:02 PM
23rd April 2013, 12:12 AM
Re: HONDA CB750 SOHC
Oops!Mistake,the flat twin Olympus is named Crown not the horizontal twin.Here I take the oportunity to say that all these
things I write and post are definetely NOT HISTORICALLY ACCURATE.I just like the subject and I like to search in the net for old Japanese bikes but somewhere between my ignorance on the subject and the google translation I am sure some wrong info is posted.As I learn more about it,I already see some mistakes in my previous posts so dont take any information for certain.This is the reason that many times I say"I guess" or "it seems" or it looks like" or (?) etc.
As for the pictures I dont post any that have a copyright sign,I try not to use any pics that include people or others that look
professional (in a studio etc).I try to post pics that look "public",from old magazines,old brochures,classic bike gatherings ,museum snapshots,photos that are already doing the round of the blogs etc.
I make these posts because I like the idea that all that info will be in one english speaking forum for anyone to see.
If by doing that I offend someone please say so and let's fix whatever problem there might be.
28th April 2013, 08:33 PM
Re: THE HONDA STORY PART 1
Hi today afew things that I found out about HOSK.
The Hosk is an important part of the Japanese motorcycle history even though they made bikes for such a sort time.
The co.starts in 1909 by Mitsushige Yamada as a bicycle and bike importer.(Yamada rinseikwan co.?)
They imported Triumph,Bsa,Calthorpe,NSU and other makes and from 1916
Harleys,Hendersons,American Excelsior,Reading Standard.
In 1913 they will become distributors of Asahi for all Japan but they don't just sell motorcycles.They employ a lathe master and a sheet metal expert(?) they make parts for the foreign bikes since parts ordered from abroad might take more than 6 months to come to Japan.
They also sell and repair clocks radios home appliances.
This is an Ariel SF 1931 barn find that was imported by Yamada
It has the Yamada badge to prove it
All these continue until 1938 when heavy import taxes make the import of bikes almost impossible.
In 1940 the only son of Mr Yamada dies in the war and he loses his interest in the co. and in 1949 Mr Yamada dies.
But he also had 2 daughters and his son in law Mr Ozeki establishes a new co.(Japan high speed engine?) with the Brand name Horse to make their own engine and other parts:speedometers ,seats ,oil pumps and others.
A brochure with the Horse brand from a blog that had old brochures of motorcycling clothes so I suppose
it advertises the overcoat.
In 1949 they hire Mr. Haruo Shimizu who in pre war times had made from scrach ,a motorcycle engine, then he made a hand made frame to install that engine and then he raced it.
The engine was an OHC 200cc copy of the AJS OHC K7 250.After the war, wounded
on the leg, he couldn't race but he entered his bike in autorace with other riders.There are stories here about some seroius gambling,races being set upetc.but I lost the details in translation.
Another brochure for the parts they were making(headlights, direction indicators etc) with the Hosk name
There is a horse with a rider in the corner that reminds of Ariel's bagde.(looks a little like a donkey to me).
Eventually he started a small production run of this engine to sell to others.
In one of the races Mr Ozeki found him and told him they can produce together
a bike with that engine and sell it through the nationwide Yamada distribution.
In 1951 they produce two prototypes in 150 cc.One OHC and one side valve.
They also start importing more European bikes:Ariel,Sunbeam,AJS,Horex,
Zundapp,Parilla and others.
An advertisment of the imports of Hosk.
In 1953 they hire Mr. Hori Yoshiro who was production manager of Asahi Miyata.Next year they announce the new brand that will make motorcycles,
the HOSK from the initials of Hori(H),Ozeki(O),Shimizu(S)andKimura(K)(he was a technician).
The HOSK badge reminds alot of the Horex one
Next episode:The Hosk production bikes.
To be continued...
Last edited by fkostas; 11th June 2013 at 01:33 PM.
28th April 2013, 09:19 PM
28th April 2013, 09:55 PM
Re: HONDA STORY SECOND PART
. In 1960 Yamaha bought Showa mainly to get access into the four stroke technology of Hosk and eventually made the XS 1 which according to every Japanese source that I read was designed by the Hosk engineers and developed together with Toyota .Yamaha has helped Toyota (I haveno idea how) with the development of the first Toyota 2000 engine.
In "western" blogs I see that the xs through the Hosk is aHorex clone but I think this is a misunderstanding that I believe has it's source in google translation.
The DA 500 I believe that it was made only as a prototype.The only pictures that I can find are of this very same bike,shot at different angles from the same meuseum (?).
I can see how the Hosk DA was similar to Horex but it has nothing to do
with the post war Horex Imperator and this becomes obvious if one sees how different the engines are.If the Hosk engineers did get inspired by Horex,
which seems to me that they did ,then the model they have in their minds
was the pre war Horex S6 and S8.A long stroke sports bike that was made
in about 100 pieces plus a few more that Tornax bought from Horex for their
Tornado model.So inspired by that ,should be the right word, because it is
difficult(but not impossible) to have a rare Horex S6 in Japan to take apart and reverse engineer it.
Horex S8.Twin 800cc OHC(I want one).
Another S8.What a work of art.(I want this one too please)
From the other hand Yamaha wanted to make "something like a Triumph"
twin but without the problems of the ageing design of the Triumph.That's why they made an engine in unit with the gearbox to avoid the oil leaks from the many gasket faces that a non unit engine has, plus an OHC because with it the engine goes to higher rpm and needs less maintenance(or it is supposed to).
If you see the engine characteristics(boreXstroke,HP,primary drive etc)it is clear that they had Triumph in their minds. Triumph in '68 was still a top selling big bike.
There might have been some inspiration from the unit construction Horex
Imperator ,since there were the same engineers that admired Horex,but that bike was ancient history in 68 the year of the first XS Yamaha.
Another story says that the Hosk engineers were developing a new OHC twin even before the Masakazu take over of Hosk.In which case there were,propably,ready designs or maybe even a pre production Hosk engine when Yamaha acquired Masakazu with the Hosk included.
All that of course is just my opinion and every body knows what Dirty Harry thought about opinions all this time ago.
The Hosk workforce.
Ah before I forget in aprevious post on Olympus I said that maybe HOSK bought the Horex-like engine from Olympus.
Now that I know a little more this doesn't seem to be true.
So that's it about Hosk.Anybody wants to know something about a specific bike?Hiko?
I have hundreds of pics of old Japanese bikes and a little bit of history for most of them.
Last edited by fkostas; 11th June 2013 at 01:27 PM.
2nd May 2013, 11:11 PM
Re: HONDA STORY SECOND PART
A little note here to say that: The Asahi brand has nothing to do with theAsahi Pentax cameras(Asahi I think means sunshine or sunrise).The olympus bike has nothing to do with the cameras with the same name.The Showa has nothing to do with the famous suspension Showa of today or with the Showa aircrafts co.( I think Showa is an era.It started early 20's and ended somewhere in the 50's or 60's.Japanese blogs sometimes mention the years by Showa.Like.."this happened during Showa 23..." Just to add to the confusion of google translation.)
Last edited by fkostas; 6th May 2013 at 03:19 AM.
11th May 2013, 02:07 PM
21st May 2013, 04:21 AM
Re: HONDA STORY SECOND PART
Today another unknown cool small industry.
The Pearl motorcycle that was made by Kosakusho Yamashita Mfg. co.,an engineering firm which was founded in 1941 to produce machinery tools(?)in Nagoya prefecture.
Nagoya for a few years had more than 80 motorcycle industries. In 1953 it became the home of the Nagoya TT.A race in public streets in the spirit of the Manx TT.The idea behind the race was to help improve the engines of the small factories of the period and it was restricted to Japanese bikes only.It was organised by the Ministry of trade and industry(?) and local authorities.In the first race there were 19 different companies participating and 57 riders.
In 1947 Kosakusho Yamashita Mfg. co.decides to enter the motorcycle market and they start designing their own engine.
In 1950 they make a side valve engine the Z53 150cc and an OHV the P53 150cc as well.
Pearl Z 150 side valve
In 1951 they install the side valve engine in a racing frame and they enter the bike in Autorace(or dirt track?).The rider was Mamoru Yamashita the 9 year old son of the founder of the industry(Yes really! 9 years old!!!)They chose to race the side valve instead of the OHV because it was lighter and easier for the kid to race.It had a special,lowered,frame.
Yamashita Jr. on the 150cc side valve racer.9 years old and he already has "The look".
In 1952 they make an OHC version of the engine,called K engine.They make a bike with the new engine called P52 150(or golden arrow ).The engineers that designed it were Imamura Masateru and Miyazaki Kyosuke.Imamura,was a successful racer on a velocette(KTT 250?) before the war.
The Pearl P52. 150cc,OHC,bevel drive,boreXstroke 56X50mm.
With the OHC K engine they prepare race bikes for autorace,dirt track,and for the Nagoya TT(only one bike for each version).In 1952 Yamashita Jr. races the OHC 150 in various dirt tracks and wins theToyohashi (?)race .
1952 Yamashita Jr.and Pearl 150cc OHC winner of the Toyahashi dirt track race.Check out the "alternative" front fork.(Cool shoes too!)
In 1953 they enter the 1st Nagoya TT with a scaled down 125 OHC and take 8th position.The same boy is the works rider for all kinds of races(!!).The racing "authorities' made an exception and gave him a racing license ,even though he was under aged.
The TT 125 OHC with Earles type fork.
In 1955 they entered the 1st Asama mountain TT,a similar venue as the Nagoya TT with this 125cc OHC bike.
The Pearl in the 1st Asama TT.OHC,123cc,54mmX54mm and Earles type fork
The times where difficult though and the Korean crisis made things worse for small industries.Mizuho who made the Cabton motorcycles and sold engines to a number of small industries,files for bankruptcy drifting with them the rest of their customers.
At the same time the government cuts the funds to the small companies and eventualy,within a few years, only the big ones survive.
It was a real slaughter but Pearl soldiers on and in 1956 they introduce a new engine.A 250cc,unit single,with bevel drive to the OHC.They market it as KM250 but they must have sold very few of it.
The pearl KM 250 of 1956.OHC,232cc,70mmX65mm,14.5Hp,4 gears.The frame is not unlicke a BMW frame.(like most of the previous street bikes they made)
The KM 250 engine.Looks very advanced for 1956.It is of the Italian school but I have never seen an engine with the bevel drive at an angle
They also make a racing version(they made a racer out of each engine they produced!)but with gears driving twin overhead camshafts.They want to enter it in the 2nd Asama TT but they don't have the funds to do it.I think they couldn't pay the,substantial,entry fee.
Mamoru Yamashita ends up racing a Masakazu (Showa) Light Cruiser 125(with a Hosk OHC engine).I think he takes the 2nd place.
After the race Pearl motors withdraws from the motorcycle market.
The DOHC engine.
Gear drive to double OHC and hairpin valve springs.Very "Italian", high performance set up.
Mamoru Yamashita became a works rider for Honda and he had a successful racing career until a serious accident(1967?)forced him to retire.
Pearl KTT 1955.250cc,bevel drive OHC,65mmX75mm,compression 7,3:1,10,5PS/5700rpm,158kg.
The parent co.,Kosakusho Yamashita Mfg. co.,continued with the production of car and airplane parts .Later doing work for Mitsubishi heavy industries (construction of wind tunnel models?)and is still alive and well doing a variety of engineering constructions and aerospace research and testing equipment for airplane construction(?)and and...A very busy company,still small with 42 employees.And guess who is the managing director.Mr Mamoru Yamashita himself.Young and enthusiastic as always,gives interviews and speeches on the Pearl motorcycle and the history of racing back then.
They even have a page dedicated to the Pearl in the Kosakusho Yamashita Mfg. co official web site.
There is still motorcycle passion in Nagoya where Mr Yamashita's headquarters are.
Pearl TT 150cc
Pearl brochure with the OHV P53 and the side valve Z53
Last edited by fkostas; 24th May 2013 at 11:21 PM.
17th June 2013, 10:57 PM
Last edited by fkostas; 18th June 2013 at 04:15 AM.
17th June 2013, 10:58 PM
Re: HONDA CB750 SOHC
for today the IMC.
IMC was one of the ,so called, assembly manufacturers,factories that were buying the engines from other industries.
It started in 1947 by Ito Tadaschi (later he changed his name to Ito Jinichi)who during the war was working for Mitsubishi aviation in the design of jigs(?).
In 1947 he established a company (Ito Movers Works?) with 3 employees to produce motorcycles in Nagoya.
The first one was the IMC (Ito motor cycle) Falcon A.It was a bicycle with a clip on engine.As it was usual with other industries of the era he used a war surplus engine that was made either to charge the batteries of the tanks or it was the starter of the tanks(?).It was a two stroke of 78 cc and it became popular thanks to it's good performance.
The IMC Falcon A with the war department surplus engine.The same engine was used by Honda for their first model
When the stock of engines dried out he approached Tohatsu to commission the production of an engine for IMC.Tohatsu agreed with the term that they were going to use the engine to market their own moped as well.
IMC made the Falcon B in 1948 and the Falcon C in '49 with the Tohatsu engine and with improvements to the frame to differentiate it from the Tohatsu.
1950 brings the model D with a Mitsubishi 150 cc engine(I think side valve),in 51 the IMC E with the same engine and rear suspension and in 52 the 150cc F and a 175 version the G model.
The IMC F with the mitsubishi 150 engine.The black ractangular"things" on the crash bars are aftermarket blinkers.
In 52 they build a new factory 100 square meters (only?) with the capacity to build 200 bikes a month!
Next year they introduce the IMC H with the 150cc OHV valve engine from Katayama industries( Olympus).
They enter it in the Nagoya TT race.They take the 23d position and the 7th place in the team awards.
In 1954 they build the K model with a Mizuho (Cabton) 250 OHV.
IMC 250 cc K model.Very Triumph like.
This was a 250 single cylinder version of the,Indian Warrior inspired, RTS 500 Cabton twin engine.
The K model was voted the best motorcycle design in a "motorcyclist"magazine contest and it became news on the national TV and together with a photo shoot with IMC bikes and pretty girls and an advertising campaign on 50 nationwide newspapers, gave much needed publicity to IMC.
The IMC K during an advertising run of 500 km.
The same year they produce 1963 motorcycles,K model and J model with a 175cc Mitsubishi side valve engine, and they become the number 14 moto industry of Japan
The 250 K again.From this angle it looks to have just one cylinder.
But the success of the K model wasn't going to last.
Mr Ito ,who,from what I read was an honorable man,a gentleman of the"old days", had an agreement with Mizuho to buy their engines with the condition that Mizuho will not sell complete bikes.
This was an old fashioned business deal that was sealed with a hand shake and no paperwork.
Next year Mizuho introduces the Mizuho 250 MJ with the same engine but with a single exhaust port and one excaust pipe and at the same time stops supplying the engines to their other customers.There was 5 different industries using the Mizuho 250 for their own bikes.
The Mizuho 250 MJ.With single excaust and other cost cutting solution looks cheaper than the IMC K.
They sell the Mizuho MJ for 135000 yen while the IMC K costs 165000 yen.
As mentioned on the Cabton-Mizuho post earlier they tried to corner the market with prices lower than the competition but they ended up cornering themselves.
They spoiled their brand image and soon went bankrupt.
IMC is forced to find another engine supplier and they end up with a Kawasaki 250 OHV engine to make the M model with the same cycle parts as the 250 K but with a swinging arm rear suspension.
The IMC M with the Kawasaki Aircraft co. engine.
The same year,1955,they make the 125 NB a 2stroke with a Fuji engine made by Gasuden(really that's the name I didn't make this up).
Gasuden was a company that,after WW2, was making a minivan and produced their own engines for it.Later Fuji used the engine for the Fujicabin three wheel car and eventually bought Gasuden and used the engines for their own bikes and to sell to other companies.
Maybe the 125 NB or a similar model with the Gasuden engine
In 1956 Mizuho goes bankrupt and many other small industries close their doors.The "natural selection", that will end up with only 4 big industries left in Japan, has started.
IMC builds a new factory in their own land.With 50 employees and a cost cutting policy they try to keep the 300 bike per month production target.
They introduce the P 200 and R 250 2 stroke twin.
The IMC 250 R with a twin engine was fast and sold well.
The engines from now on are all from Gasuden exept one more Kawaski engined 250 OHV the MS 250 with Earles fork.
A brochure from'57.At the bottom right the MS 250.
In 1957 they sell 2528 bikes.
In 1959 the Ise Bay typhoon(?) hits the factory that submerges into water.
The co. has to stay closed for 2 months.
At the same time the popularity of the small car and of Honda and Yamaha motorcycles rises.
IMC finds themselves in debt for the first time.They continue with 2 strokes of 125-250 cc.In 1960 they make only 52 bikes per month.
In 1961 they stop production of motorcycle but they still make parts for the older models.
Finally in 1962 they sell their factory to pay back the debts and they close the doors.
The IMC merged with Nissan diesel and nothing was heard of it any more...
At the blog that I found this picture the caption said:IMC with Mitsubishi engine.
I don't know of any Mitsubishi engine with upright cylinder and to me it looks like the M model with the Kawasaki engine from the brochure a few pictures back.The picture must be from the photos with the girls.This is the first time I see a Japanese bike of the era with a double seat.Or is just a cover pretending to be double seat?
Last edited by fkostas; 21st June 2013 at 03:55 AM.